Open-tipped carbon nanotubes with a large amount of subnanopores and open ends on the tube wall were conveniently prepared by an improved anodized aluminum oxide template growth. The hydrogen storage was measured based on a volumetric method. Adsorptions of 6.46 and 1.12 wt % were achieved at 77 K and room temperature, respectively. Compared to hydrogen adsorption of other carbon materials, rough wall surface, opening tips, subnanopores, and opening ends on the wall were attributed to greatly enhanced hydrogen storage. (C) 2003 American Institute of Physics.